The prostate gland is part of the male reproductive system. It consists of two lobes in front of the rectum and just below the bladder. The prostate gland also surrounds the urethra, the canal through which urine passes out of the body. The prostate gland has two main periods of growth. The first growth period is during puberty. However, during a man's mid-twenties, the prostate gland begins to grow again and continues to do so for the remainder of life. As the prostate gland grows, several problems often occur as a result of excessive growth. Rarely do such afflictions occur before forty, but as a man's age increases, the likelihood of prostate gland afflictions increases significantly.
Benign Prostate Hyperplasia (BPH) is the later growth of the prostate gland causing symptoms such as pain, frequent urination and inability to drain the bladder. Fortunately, a digital rectal exam can often lead to early detection of BPH and several effective treatment modalities exist. For example, drugs such as finasteride, transurethral microwave procedures, transurethral needle ablation, and surgical treatments are available.
Several approaches to treatment by heating the prostate are known. See, for example, U.S. Pat. Nos. 6,477,426, 6,592,579, 6,402,742, 6,142,993, 5,865,788, 5,385,544, 6,490,488, and 6,895,282. Such known heat treatments have difficulty in targeting the prostate without heating the urethral and rectal walls, which can result in destroying healthy tissue. As a result, monitoring of the temperature of the prostate and surrounding areas is critical to successful procedures. In order to measure accurately the rectal wall temperature and, thereby, monitor the prostate temperature as well, it is necessary that the rectal probe be of sufficient size to press against the rectal wall at the appropriate location. However, such size causes pain and discomfort upon insertion, while after insertion, discomfort is often negligible. Known techniques for monitoring internal temperature, such as those disclosed in U.S. Pat. Nos. 6,348,039, 5,792,070, 5,404,881, 6,475,140, 6,868,290, and 4,046,139, can provide not only poor performance but also discomfort during insertion and complexity of operation.